With all cleaning methods a wall-to-wall carpet needs to be thoroughly vacuumed prior to cleaning to remove any heavy soil such as silicates (the primary constituent of soil), without this pre-vacuuming, dirt and sand are forced to the backing of the carpet.
Absorbent Powder / Dry Extraction Cleaning: An absorbent granular material that has been incorporated into a mixture of detergent, solvent and water is brushed into the carpet pile with a machine incorporating a double cylindrical brush. Once the material has dried the carpet is vacuumed to remove the powder and the soil that it has captured. The best use for the absorbent powder cleaning method is the commercial installation where the carpet is cleaned regularly and requires quick drying.
Bonnet/Spin Pad: This method in appearance is similar to the rotary shampoo method. The machine used is essentially the same. A detergent is usually sprayed onto the carpet. A rotating absorbent pad spins and agitates the carpet fibers as the soil is collected into the pad. This method improperly preferred on cut pile carpet can cause untwisting of the face pile. While this method is reasonably quick drying it must be done more often as it is more of a surface cleaning. The best use for this method of cleaning is the commercial installation where they clean regularly and require quick drying.
Cylindrical Foam Shampoo: The cylindrical foam method uses a machine with an air compressor that whips the shampoo solution into heavy foam. The foam is brushed into the carpet with a cylindrical brush. Once the carpet has dried it is vacuumed to remove the shampoo and the particles that have theoretically bonded to it. Not all of the shampoo and soil is actually captured but instead much of it is forced deeper into the pile. While this method is reasonably quick drying it must be done more often as it is more of a surface cleaning. The best use for cylindrical foam cleaning is the commercial installation where they clean regularly and require quick drying.
Rotary Shampoo: The Rotary shampoo method uses chemicals similar to those used with cylindrical foam. The rotary floor machine usually has an attached solution tank for the shampoo solution. The diluted solution is fed through a tub to a “shower-feed” where it is applied to the carpet. While the shampoo is being applied a round brush on the machine is scrubbing the carpet. This shampoo method uses more moisture than the cylindrical brush method. The rotary shampoo method is not recommended for use on cut pile carpet as it can cause untwisting of the face pile.
Steam Cleaning or Hot Water Extraction: With this method a non-foaming detergent is injected into the carpet fibers and is almost simultaneously vacuumed out of the carpet taking the dirt and soil with it. The extraction method when performed a skilled technician and quality chemicals will leave very residue to attract to soil. In the hands of an unskilled person the carpet can be over-wet.
Optical Brighteners (color brighteners): While not a cleaning method, optical brighteners are found in some cleaning products. These brighteners or dyes can make a carpet appear cleaner while at the same time having a harmful effect on carpet fibers. Technical people in the carpet industry have unanimously taken a stand against the use of brightening agents in the cleaning process. But, even with all of the adverse publicity, optical brighteners or color brighteners, as they are often called, are still used in some spot cleaning products, shampoo, dry-foam and extraction detergents. Optical brighteners are actually dyes, which reflect the light and eventually cause yellowing in carpet fibers. For this reason alone they should not be used for normal carpet maintenance.
